WASHINGTON — Most Americans will be able to get an extra hour of sleep this weekend thanks to the annual shift back to standard time. Officially, the change occurs at 2 a.m. Sunday, but most people will set their clocks back before hitting the sack Saturday night. Remember, it’s fall back an hour. Otherwise, you’ll be an hour early on Sunday for church, golf, brunch or whatever. Residents of Hawaii, most of Arizona and some U.S. territories don’t have to change since they do not observe daylight-saving time. Public safety officials say this is also a good time to put a new battery in the smoke alarm. Daylight saving time returns on the second Sunday in March.